The aim of these studies is further our understanding of the control mechanisms regulating gastric emptying. These control mechanisms are mediated by hormones and nervous reflexes and combinations of both. We intend to examine two aspects, ie. effects on Auerbach's plexus and behavior of tryptophan. Using extracellular recording techniques with glass 3M sodium chloride filled electrodes or platinum wire electrodes, we intend to study the effects of perfusing small intestine strips with a variety of agents known to inhibit gastric emptying in the intact animal. These perfusates are hypertonics solutions, acid, fatty acids and tryptophan. These agents will be tested in isolated tissue baths in which the longitudinal muscle has been stripped off to expose Auerbach's plexus lying on the circular muscle. Spike burst actional potentials will be recorded on an oscilloscope and kept permanently on a tape record. The second part of the project will be concerned with the tryptophan, an amino acid with potent inhibitory on gastric emptying. We intend to study, in Ussing chambers, the uptake and transport of tryptophan compared to other amino acids to determine if this accounts for its's potent effects on emptying. Studies of conductance, short circuit current, sodium dependence and competition will also be done to further define its action.